1. Field
Embodiments described herein generally relate to amino-aldehyde resins. More particularly, such embodiments relate to methods for making and using amino-aldehyde resins.
2. Description of the Related Art
Typical adhesives used in the production of cellulose based products such as medium density fiberboard (“MDF”), plywood, and particle board include amino-formaldehyde resins such as urea-formaldehyde (“UF”), melamine-formaldehyde (“MF”), and melamine-urea-formaldehyde (“MUF”) resins. While these resins produce cellulose based products having desirable properties, such as strength, these resins release formaldehyde into the environment during the production of the resin, during the curing of the resin/cellulose based product, as well as, from the final cellulose based product made using the resin.
Various techniques have been used to reduce the amount of formaldehyde released from amino-formaldehyde resins. Such techniques have used the addition of formaldehyde scavengers to the resin. Other techniques, alone or in combination with the scavengers, have used various modifications to the synthesis steps used to make the amino-formaldehyde resin, such as the addition of urea as a reactant late in the resin synthesis. These attempts to reduce formaldehyde emission, however, are accompanied with undesirable effects such as longer cure times, reduced shelf-life of the resin, reduced product strength, reduced tolerance for processing variations, and/or inferior moisture resistance.
There is a need, therefore, for improved methods for making amino-aldehyde resins and products therefrom having reduced formaldehyde emission and/or requiring reduced cure time.